Abrasive cutting machine and method



Feb. 18, 1936. D. LEWIS ETAL ABRASIVE' CUTTING MACHINE AND METHOD FiledApril 18, 1954 2 Sheets-Sheet l INVENTORS OARTREY LEW/6 W/LFR/D 1..wAL-sH. BY WALTER B. LA$HAR,J'R

ATTORNEY Feb. 18, 1936.

D. LEWIS ET AL ABRASIVE CUTTING MACHINE AND METHOD 2 Sheets-Sheet 2Filed April 18, 1934 INVENTORS VDVfIRTREY LEW/s.

LFR/O L. WALSH,

- WALTER B. LAHAR,JA

TTORNEY Patented Feb. 18, 1936 FlCE ABRASIVE CUTTING MACHINE AND METHOD.Dartrey Lewis, Boston, Mass., and Wilfrid L;

tion of New York Application April 18, 1934, Serial No. 721,128

9 Claims. 01. 51-98) This invention relates to an improved method andapparatus for cutting various substances, more particularly those of a.brittle nature, although it is usefully applied to the cutting of anyhard substance whether or not having the characteristic of brittleness,such as various steels and other metals, plastic compositions, hardrubber, etc. The invention involves, as its principal feature, thecutting of such materials while they are subject to the action of astream of water or other suitable liquid as distinguished from otherprocesses recently developed wherein they are submerged in a body ofwater. We are aware of the fact that it has already been found that,when cutting metals with a thin abrasive wheel, it is of great advantageto submerge the material in a liquid-more commonly water-the result ofwhich is a smooth, clean cut with a substantially perfectly planesection without burrs on its edges and without any deleterious efiectsfrom burning or undue heating. We have found that, while submergence ofthe materials during cutting with wheels of the type above-mentioned ishighly advantageous, there are many cases in which complete submergenceor immersion can be dispensed with and a stream of water directed on thework in the region of cutting, provided such stream of water be ofsuitable volume and be properly directed and confined.

With the foregoing and other objects in' view, the invention consists ina certain method and improved means for carrying out the method, as willbe more clearly disclosed in connection with the accompanying drawings,but it is to be understood that we are not limited to the specificapparatus shown, it being quite feasible to carry out the method invarious other apparatus.

Referring to the drawings,

Fig. 1 is an elevation of the machine partly in section;

Fig. 2 is a view on the line 2-2 of Fig. 1; and

Fig. 3 is a plan view on the line 33 of Fig. 1.

These drawings show the embodiment of the invention in a machine whichhas proven very efiicient in carrying out the process referred to. Itcomprises a bed I which may be provided with vertical peripheral walls II to form a reservoir or container for water or other liquid employed inthe cutting operation, as will be hereinafter more particularly pointedout. This bed or container may be mounted on any suitable support suchas the pedestal l4. The container may be provided with rearwardlyextending brackets l5 on which may be pivotally mounted, as by ashaft-J6, a frame I'l carrying the thin abrasive cutting wheel indicatedat l8 and the power means for driving this wheel, such as an electricmotor l9. .-In the present instance, the wheel is removably mounted on ashaft 20 running in bearings 2| in the frame I! and is driven by asuitable flexible drive. such as a V-belt drive 22 running over pulley23 on the shaft 20 and also on a drive pulley (not shown) carried by themotor shaft in the usual manner. for adjusting the tightness of thisbelt drive, and, in the present instance, the motor is carried on aframe 25 secured to an upright bracket 26 pivoted in the frame H at 21between arms 28. This bracket 26 also has a lug 29 provided with anarcuate slot 30 struck with the pivot 21 as its center. An adjustableclamping bolt 3| carried by the lug 32 on the frame I'l provides a meansrequired. Preferably the motor should overbal ance the wheel somewhat soas to retain the wheel in the upright position-that is, away from thework between cutting operations. An adjustable limit stop is carried bythe'frame l1 to limit downward movement of the wheel to prevent itsbeing shifted further than necessary for severing the particular sectionbeing out. In the construction shown, this comprises a rod 33 threadedinto a lug 34 on the frame and having a crank handle 35 whereby it maybe adjusted. At its lower end it is adapted to engage an upwardlyextending stop wall 36 carried by the container ID to limit downwardmovement of the wheel. The frame I! may be rocked on its pivot to shiftthe wheel to and from the work by any suitable handle "a adjustablysecured to the frame at Mb.

The wheel is preferably enclosed in a suitable safety guard so that,should it break, there will be no flying pieces to injure the operator.This guard is illustrated asa sheet metal member 42 extending-over andenclosing the wheel and including an enclosing wall 43 on one side. Onits opposite side it has an opening 44 of sumcient diameter to permitinsertion and removal of the wheel for application to and removal fromthe driving shaft 20. After the wheel is applied, this opening is closedby a cover-plate 45, preferably detachably secured in position by anysuitable means. The rear wall 43 is provided with an arcuate slot 41through which the shaft 20 His also preferred to provide means i extendsand permits up and down movement of the wheel. The guard may be mountedby any suitable means.

As the wheel l8 during the cutting operation rotates, it will be evidentthat it tends to carry any liquid that it may pick up into the guard. Toprevent this a stripper plate 48 is provided, this stripper plateextending laterally on opposite sides of the rear portion of the wheel.This plate may be mounted on the guard as indicated at 49 and maycomprise a single plate 48 with a narrow slot which affords justsufiicient clearance to permit the 'wheel to rotate. This plateefiectively strips from the wheel any liquid that may be carriedupwardly with it. Of course, the material to be cut must be held in theproper position in the container. Satisfactory means for doing this maycomprise the supporting blocks 52 and 53 separated by a narrow space 54to permit the abrasive wheel l8 to pass between them. These blocks haveproperly shaped notches 55 to receive the work, which, in the drawings,indicated, consists of a tube l3. These notches may be of variousshapes, but they are preferably tapered so that the work is firmly held.Of course, certain sections would be more stable in other shapes thanV-notches, and, consequently, for particular jobs the shape of thenotches would be adapted accordingly. Manually operated means are alsoprovided for clamp- ,ing or holding the work in these supporting blocks.In the present instance this clamping means comprises a lever 56 pivotedat 51 to lugs 58 on the forward wall of the container l0, and this leverincludes a pair of spaced arms 59 and 60 extending at their free endsover the blocks 52 and 53. They are spaced sufficiently to permit thewheel l8 to pass between them, and these arms, with the blocks 52 and53, provide means for clamping and holding the work on both sides of thewheel. The handle 6| permits lifting of the arms 59 and 60 to releasethe work and also to control the movement of the arms 59 and 60 to thework holding position. It has been found advisable, however, whencertain materials and shapes are being cut, to provide yieldingresilient means for holding these clamps against the work. Thus thelever 56 is provided with an arm 62 carrying adjustable screw 63threaded in the arm and engaging the end of a slidable block 64 mountedin a recess in the container l0. In this recess is a spring 65 whichtends to force the block 64 out against the screw 63 and to clamp thearms 59 and 60 down on the work. After adjustment, the screw 63 may belocked in ad- Justed position by lock-nut 66, and it will be evidentthat, with this construction, the tension of the spring may be adjusted,and, as a consequence, the pressure of the clamp on the work.

It has been found that in cutting glass tubes and particularly thin wallglass tubes, they should not be clamped too firmly. This adjustment ofthe pressure of the spring 65 is very effective in securing a properyielding resilient pressure. It also seems advisable to have yieldingresilient pads to contact with the work especially when glass tubes arebeing cut, and we further use such pads 61 preferably of live rubber orsimilar material.

To the container I!) there is also aifixed a block 68 provided with apassage 69 .having a curvature slightly greater than that of the wheeland located with its center of curvature approximately in the axis ofrotation of the wheel at the average position of the latter when cuttingthrough a section-that is to say, the center of curvature of the conduitwould ordinarily be in the axis of rotation of the wheel when the latterhad about half out through the average section that the machine isdesigned to operate upon. The walls of the passage 69, it will be noted,are partially composed of the flanges 10 on either side of the wheel,these flanges extending toward each other to such an extent that thewheel is rotating practically in a very narrow slot.

A source of water supply such as the pipe ll leads to the passage 69,and wateror for that matter-any liquid desired, may be led to thepassage 69, whence it will flow down the passage and into the container,whence it may be run off to a waste pipe or circulated by a pump forrepeated use, if desired.

In using the machine, the materialwhich for purposes of illustration mayconsist of the glass is important that the conduit 69 be so con--structed that the stream of water emerging from it shall impinge on anarea which includes the point of entrance of the wheel into the cut,this region being sufliciently large to always include that point as thecutting progresses. Of course,

it is obvious that for several reasons it is desirable that the wheelrun in a fixed plane in order that lengths of uniform thickness may becut from rods, bars, sheets, and the like, and, furthermore, to avoidbreakage. It is therefore important that the cross-section area of theconduit be symmetrically designed with respect to the plane of the Wheelso that the pressure on both sides of the wheel will balance, since wehave discovered that wheels of the gauge thickness that we employ are,when rotating at high speeds, easily deflected sidewise by very slightunbalanced pressures on their respective faces. The velocity of thewater or other liquid supplied to the entrance end of the conduit neednot be high since it derives a very high velocity by the centrifugalforce imparted by the rapidly revolving wheel, the speed of which wouldvary from 1200 to 2500 revolutions per minute, depending upon the lengthof the cut and the nature of the material being cut. The volume of thestream should, however, be sufficiently large so that the regioncovering and surrounding the cut is virtually immersed in the liquid.

We claim:

1. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive Wheel, a frame on which the said wheel is rotatablymounted, the said frame being pivotally mounted to permit it to tilt andto move the wheel bodily in its plane of rotation, and a member providedwith an arcual conduit for liquid mounted in the plane of rotation ofthe wheel and approximately concentric therewith, said conduit beingprovided with a narrow slot through which the edge of the wheel may,when tilted, extend into the conduit and rotate therein, said conduitbeing symmetrical with respect to the plane of travel of the wheeltherein.

2. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a frame on which the said wheel is rotatablymounted, the said frame being pivotally mounted to permit it to tilt andto'move the wheel bodily in its plane of rotation, and a member providedwith an arcual conduit for liquid mounted in the plane of rotation ofthe wheel and positioned to discharge liquid to the cutting region, saidconduit being provided with a narrow slot through which the edge of thewheel may, when tilted, extend into the conduit and rotate therein.

3. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a frame on which the said wheel is rotatablymounted, the said frame being pivotally mounted to permit it to tilt andto move the wheel bodily in its plane of rotation, and a member providedwith an arcual conduit for liquid mounted in the plane of rotation ofthe wheel and approximately concentric therewith, said conduit beingprovided with a narrow slot through which the edge of the wheel may,when tilted, extend into the conduit and rotate therein.

4. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel,- a frame on which the said wheel isrotatably mounted, the said frame being pivotally mounted to permit itto tilt and to move the wheel bodily in its plane of rotation, and a.member provided with an arcual conduit for liquid mounted in the planeof rotation of the wheel and approximately concentric therewith, saidconduit. being provided with a slot through which the edge of the wheelmay, when tilted, extend into the conduit and rotate therein, saidconduit being symmetrical with respect to the plane of travel of thewheel therein.

5. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a frame on which the said wheel is rotatablymounted, th said frame being pivotally mounted to permit it to tilt andto move the wheel bodily in its plane of rotation, and a member providedwith a conduit for liquid mounted in the plane of rotation of the wheeland positioned to discharge liquid to the cutting region, said conduitbeing provided with a narrow slot through which the edge of the wheelmay extend into the conduit and rotate therewith.

6. In an abrasive-cutting machine, means for clamping the material to becut, a thin abrasive ably mounted, the said frame being pivotallymounted to permit it to tilt. and to move the wheel bodily in its planeof rotation, and a. member provided with a conduit for liquid mounted inthe plane of rotation of the wheel and positioned to discharge liquid tothe cutting region, saidconduit being provided with a slot through whichthe edge of the wheel may extend into the conduit and rotate therewith.i

7 In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a. frame on which the said wheel is rotionedto discharge liquid to the cutting region,

said conduit being provided with a slot through which the edge of thewheel may, when tilted, extend into the conduit and rotate therewith.

8. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a frame on which the said wheel is rotatablymounted, the said frame being pivotally mounted to permit it to tilt andto move the wheel bodily in its plane of rotation, and a member providedwith an arcual conduit for liquid mounted in the plane of rotation ofthe wheel and approximately concentric therewith, said conduit being'provided with a narrow slot through which the edge of the wheel mayextend into the conduit and rotate therein, said conduit beingsymmetrical with respect to the plane of travel of the wheel therein.

9. In an abrasive cutting machine, means for clamping the material to becut, a thin abrasive wheel, a frame on which the said wheel is rotatablymounted, the said frame being pivotally mounted to permit it to tilt andto move the wheel bodily in its plane of rotation, and a member providedwith an arcual conduit for liquid mounted in the plane of rotation ofthe wheel and approximately concentric therewith, said conduit beingprovided with a slot through which the edge of the wheel may extend intothe coin duit and rotate therein, said conduit being symmetrical withrespect to the plane of travel of the wheel therein.

DAR'I'REY LEWIS. WIIFRID L. WALSH. WALTER B. LASI-IAR, Ja.

